SOX2 and neoplasm: We have previously identified two CSC subpopulations within mHNcSCC: an OCT4+/SOX2+/NANOG+/KLF4+/c-MYC+ subpopulation within the tumor nests (TNs) and an OCT4+/SOX2+/NANOG-/KLF4+/c-MYC+ subpopulation within the peritumoral stroma (PTS) (25).